1. Technical Field
The present invention relates to an improved data processing system and, more particularly, to matching the reference voltage of interface chips to corresponding components.
2. Description of Related Art
Currently, many of the more complex computers that are used for services such as web servers are multiprocessor computers. These computers have many planars or large cards housing the major central electronics complex of the system. These systems may have several node planars housing multiple processors and associated components interacting with several memory planars and Input/Output planars which may be connected to one or more drawers holding adapters to various input/output devices or networks.
These systems often have a xe2x80x9cservice processorxe2x80x9d that is used to perform many tasks that affect the computer as a whole, such as, for example,initializing the processors and support chips, and monitoring the temperature of the computer so that the exhaust fan may be turned on and off at appropriate times. The service processor may also monitor other resources within the system shared by the many different host operating systems that may be executing on the computer.
Systems such as these are very expensive, and are often updated with new parts or components rather than being completely scrapped in favor of a newer machine. However, often the next generation module or component, such as a processor, runs at a different voltage than its predecessor. Therefore, the interface between the new generation modules and the older ones is different. Current methods to solve this problem require that the entire planars in which the new generation module is to be placed be replaced or jumpers and redundant circuits are used to change the interface voltage to match the next generation module. However, such solutions are cumbersome and often expensive. It would be desirable to have a system in which the interface voltage is automatically modified to comply with the requirements of the next generation module that is placed into the system.
The present invention provides a method, system, and computer program for updating a reference voltage for a interface chip to a component of a data processing system. In one embodiment, a service processor reads the voltage requirements from a vital product data (VPD) module for each component within the data processing system and determines whether the voltage requirement for any component differs from a default voltage value. If any component has a voltage requirement that differs from the default value, then the service processor sends a signal to a JTAG controller or voltage selector within the interface chip corresponding to the affected component changing a register bit that results in the Input/Output drivers group corresponding to the affected component using a reference voltage that matched the requirements of the component rather than the default reference voltage.